SU599883A1 - Mill for manufacturing of welded straight-seam tubes - Google Patents

Description

one

This invention relates to the manufacture of welded pipes.

A pipe forming mill is known, containing molding stands with horizontal rollers forming open and closed gauges and stands with vertical idle rollers. In addition, the mill is equipped with traverses, in which cassettes with rollers are installed, forming the upper part of the caliber. The lower part of the gauges of the part of the forming stands is formed by horizontal driven rollers and side idler rollers 1.

The disadvantages of this mill are the shaping of the edges of the strip in the first stand with open gauges, the impossibility of producing thin-walled tubes, a large number of stands and a large stock of forming tools.

Also known is a mill for forming tubes with a hearth geometry with a circular cross section, containing two open gauge stands, a lower supporting roll, three closed gauge stands, and rollers (cams) for forming the peripheral parts of the strip 2.

The disadvantages of this mill are round calibration of the forming tool, installation of roller entries so that they form the peripheral parts of the strip from the first stand with open calibers to the first closed stand, the roller is short (as a result, it forms the peripheral part of the strip only in the immediate blobs from the edges), shafting the width of the rolls of open calibers and, as a result of this, non-completeness, except for thin-walled pipes, production on this device of pipes of the usual type. Another disadvantage is the complexity of adjusting the curved axis of the mold.

Of the known mills, the closest in technical essence is a mill for the penetration of straight welded pipes containing molding cells with horizontal drive rolls forming open and closed gauges placed between the cages roller wiring, welding and pulling stands 3.

The disadvantage of this mill is the impossibility of obtaining high-quality thin-walled pipes, since when the edges are molded, in the first open-gauge cells, corrugations appear on the edges.

The aim of the invention is to improve the quality of the molding of the mold by creating an optimal geometry of the center of the molding.

This goal is achieved by the fact that the lower rolls in the forming cells with an open caliber are made with a radius of curvature that is 1.1-5.0 times the radius of curvature of the upper rolls.

Such an embodiment of the device allows to obtain an optimal geometry of the forming center, creating the most favorable deformation conditions (without forming corrugations) for high-quality molding and welding of both standard assortment and thin-walled pipes with a ratio of diameter to wall thickness significantly exceeding 50.

FIG. 1 shows the camp, general view; in fig. 2-8 - rolls of forming stands, side view; in fig. 9 is a section along A-A in FIG. one; in fig. 10 is a section according to BB in FIG. one; in fig. 11 is a section along BB in FIG. one; in fig. 12 is a cross section along L-D in FIG. one; in fig. 13 is a section according to D-D in FIG. one.

The mill for the production of welded pressure pipes contains molding stands with horizontal drive rolls forming an open gauge in stands 1 and 2 and a closed gauge in one or two stands x 3, non-driven rollers 4 located between stands 1 and 2, non-driven rollers 5 located between the cages 2 and 3, and the non-driving upper pressure rollers 6 (one and more), mounted behind the cages with a closed caliber. The barrels of the rolls of stands 1 and 2 are made so that the radii of curvature of the lower rolls are larger than the radii of curvature of the corresponding upper rolls RB. The supporting rollers have a rectilinear generatrix, while the axes of the rollers are inclined to the horizontal axis at an angle ai 15 ° + 90 ° (Fig. 10). The rollers 5 are calibrated on an open oval and are intended for forming the peripheral parts of the strip. The angle of inclination of the axes of the rollers 5 to the horizontal axis varies within a2 90 ° + 5 ° (Fig. 11-13). Moreover, in one or two sections there are lower support rollers. The upper rolls of the stands 3 have a split washer. Behind the stands with closed calibers (in the direction of metal movement), pressure rollers 6 are installed that have a split face, and with several rolls, the thickness of the face decreases as they move away from the stands with closed calibers. The edges of the billet are welded in the welding stand or welding rolls 7. Behind the welding stand there is a pull (ironing) stand 8, which has a closed oval gauge. Calibration stands 9 contain horizontal and non-driven vertical rolls, which form a closed gauge with calibration, smoothly passing from oval to circle. In order to facilitate the task of the strip, on the entrance side of the mill, driving horizontal rolls 10 with a cylindrical barrel and vertical non-driven guide rollers I. are installed.

The mill operates as follows. The strip is set in the first molded stand 1 with rollers 10 with a smooth barrel. In this case, the guide rolls 11 perform an auxiliary role, setting the strip to the mill strictly along the axis of the molding. Rolls in cages 1-3, non-driven rollers 4 and 5, as well as pressure rollers 6 and welding rollers 7 create the optimum molding center for production

pipes, including thin-walled. The welding rolls compress the edges of the forming tube stock by welding them. T nushcha (ironing) to; fly 8 contributes to the creation of the optimal geometry of the center of forming in the area of the welding stand in the unsteady process of the mill (at the time of entering the strip into the mill). The rolls of the calibration stands 9 calibrate the welded oval tube to the round section of the finished tube.

The proposed mill for the production of straight-seam welded pipes, in comparison with the best examples of similar equipment, allows improving the quality of molding, significantly expanding the range of manufactured

pipes, and also to reduce the number of stands and the park of the forming tool.

The test of the proposed construction of the mill was carried out on an industrial mill 51 -152 Dnipropetrovsk pipe rolling

plant them. V.I. Lenin. Three main stands with horizontal drive rolls were used to form the pipe billet, an additional non-driven stand and two groups of roller wires, installed

instead of edger rolls between the main stands. The length of the molding line was 25 diameters of the finished pipe.

Experimental welding of pipes with a diameter of 152X1.5 mm in a mill for the production of straight welded pipes has shown that this mill enables high-quality molding of the edges of the billet and welding of thin-walled pipes, it is economically beneficial in terms of reducing the wall thickness of the pipe being welded, reducing the number of stands, reducing narka forming tool compared with the known mills.

Claims (3)

Invention Formula Mill for the production of welded straight steel pipes containing molding stands with horizontal drive rollers forming open and closed gauges placed between the rollers, roller lines, welding and thickening cages, characterized in that, in order to improve the quality of the molding by creating the optimum geometry of the center of the molding, the lower rollers in the forming cells with open caliber are made with a radius of curvature greater than the radius of curvature of the upper rolls in 1,1- 5.0 times. Sources of information taken into account in the examination 1. USSR author's certificate L212966, cl. At 21C 37/06, 1966. 2. The patent of Germany No. 1752560, cl. 7B 37/08, 1973. 3. US patent number 3.014.118, cl. 219-59, 1961. W / 7 rig, F fg 7 Fig 13 Oig 12 Vuz II-fPi-Z S